Derivatives, Sold and Purchased Credit Derivatives (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2015	Dec. 31, 2014
Details of Sold and Purchased Credit Derivatives [Abstract]
Fair value liability	$ 743	$ 943
Notional amount Protection sold	10,583	12,304
Notional amount Protection purchased with identical underlyings	6,042	6,888
Notional Net protection sold	4,541	5,416
Notional Other protection purchased	11,835	9,771
Non-investment grade [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Notional amount Protection sold	5,338	6,207
Corporate bonds [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Fair value liability	11	23
Notional amount Protection sold	5,316	6,344
Notional amount Protection purchased with identical underlyings	3,985	4,894
Notional Net protection sold	1,331	1,450
Notional Other protection purchased	$ 2,499	$ 2,831
Corporate bonds [Member] | Minimum [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Derivative range of maturity dates	Jan. 01, 2015	Jan. 01, 2015
Corporate bonds [Member] | Maximum [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Derivative range of maturity dates	Dec. 31, 2021	Dec. 31, 2021
Corporate bonds [Member] | Non-investment grade [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Notional amount Protection sold	$ 1,886	$ 2,904
Structured products [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Fair value liability	483	654
Notional amount Protection sold	854	1,055
Notional amount Protection purchased with identical underlyings	536	608
Notional Net protection sold	318	447
Notional Other protection purchased	$ 224	$ 277
Structured products [Member] | Minimum [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Derivative range of maturity dates	Jan. 01, 2017	Jan. 01, 2017
Structured products [Member] | Maximum [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Derivative range of maturity dates	Dec. 31, 2052	Dec. 31, 2052
Structured products [Member] | Non-investment grade [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Notional amount Protection sold	$ 682	$ 874
Credit default swap [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Fair value liability	0	0
Notional amount Protection sold	952	1,659
Notional amount Protection purchased with identical underlyings	860	777
Notional Net protection sold	92	882
Notional Other protection purchased	$ 1,183	$ 1,042
Credit default swap [Member] | Minimum [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Derivative range of maturity dates	Jan. 01, 2015	Jan. 01, 2015
Credit default swap [Member] | Maximum [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Derivative range of maturity dates	Dec. 31, 2020	Dec. 31, 2019
Credit default swap [Member] | Non-investment grade [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Notional amount Protection sold	$ 196	$ 292
Commercial Mortgage Backed Securities [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Fair value liability	229	246
Notional amount Protection sold	844	1,058
Notional amount Protection purchased with identical underlyings	660	608
Notional Net protection sold	184	450
Notional Other protection purchased	$ 460	$ 355
Commercial Mortgage Backed Securities [Member] | Minimum [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Derivative range of maturity dates	Jan. 01, 2047	Jan. 01, 2047
Commercial Mortgage Backed Securities [Member] | Maximum [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Derivative range of maturity dates	Dec. 31, 2057	Dec. 31, 2063
Commercial Mortgage Backed Securities [Member] | Non-investment grade [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Notional amount Protection sold	$ 5	$ 0
Asset-backed securities [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Fair value liability	19	19
Notional amount Protection sold	49	52
Notional amount Protection purchased with identical underlyings	1	1
Notional Net protection sold	48	51
Notional Other protection purchased	$ 75	$ 81
Asset-backed securities [Member] | Minimum [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Derivative range of maturity dates	Jan. 01, 2045	Jan. 01, 2045
Asset-backed securities [Member] | Maximum [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Derivative range of maturity dates	Dec. 31, 2046	Dec. 31, 2046
Asset-backed securities [Member] | Non-investment grade [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Notional amount Protection sold	$ 1	$ 1
Other Credit Derivatives [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Fair value liability	1	1
Notional amount Protection sold	2,568	2,136
Notional amount Protection purchased with identical underlyings	0	0
Notional Net protection sold	2,568	2,136
Notional Other protection purchased	$ 7,394	$ 5,185
Other Credit Derivatives [Member] | Minimum [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Derivative range of maturity dates	Jan. 01, 2015	Jan. 01, 2015
Other Credit Derivatives [Member] | Maximum [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Derivative range of maturity dates	Dec. 31, 2025	Dec. 31, 2025
Other Credit Derivatives [Member] | Non-investment grade [Member]
Details of Sold and Purchased Credit Derivatives [Abstract]
Notional amount Protection sold	$ 2,568	$ 2,136